The invention relates to a circuit arrangement for connecting information transducers in a program controlled data processing system, in particular a program controlled telecommunication switching system.
In such systems, the transfer of information between the input and output lines connected to a line connection unit always occurs over a central memory. The storage areas in the central memory are connected to the input lines and can be reached over input code transducers. Each corresponding storage area contains an address datum determining the desired consumer or output line, and under the influence of the latter address datum, consumer line can be reached over output code transducers.
In a program controlled data processing system employed as a dial exchange system, which has recently become known, the incoming connections, the so-called feed lines (incoming lines), and the outgoing connections, the so-called consumer lines, are connected to a line connection unit. The input code transducer and the output code transducer are an essential component of this line connection unit, to which the feed and consumer lines are connected over system connection units. The system unit has access, over a control device attached to the line connection unit, to a central store, which contains a core store as an essential component, along with the control equipment. This system is described in an article entitled EDS - A New Electronic Data Switching System for Data Communication, in the publication "Nachrictentechnische Zeitschrift", (1969), No. 8, pages 444 to 463. (The latter publication is printed in the English language.) Further, the latter mentioned control equipment is described, as well, in commonly assigned U.S. application Ser. No. 870,298, now abandoned, and U.S. Application Ser. No. 233,662, which is a continuation in part of the latter application now U.S. Pat. No. 3,775,754.
In such a system a transmission of information between feed and consumer lines takes place in a manner such that each polarity change within a binary message is directed to the central memory or store and there entered in a storage region associated with the feed line; this region is called a storage cell in the following. This storage cell contains, along with other information, the address of the consumer line for which the information is intended. The indentification of requesting feed lines, or the feed lines which present a piece of information, e.g., a polarity change, occurs in the input code transducer. The storage cell in the central store associated with this feed line is then controlled over the transmission sequence control of the line connection unit. On the basis of the dial information, which was fed into the central store during establishment of the connection over the feed line in the same manner, the address information is available there over the desired consumer line for the entire duration of a connection. To transmit the information between the feed line and the desired consumer line, the address of the desired consumer line is given to the output code transducer once again over the transmission sequence control. The identification of the consumer lines then takes place in the output code transducer.
It is often necessary to switch information transducers, for example, coding or decoding devices or compensating networks into a connection. In particular the switching in of the compensating networks is frequently of considerable importance, since the transmission characteristics of the lines connected to an exchange system can be influenced by disturbances either continuously or from time to time. It is known to attach the compensating networks permanently to the lines, although this results in the disadvantage that inefficient use is made of networks due to the cyclic fluctuation of traffic. Further, there is the disadvantage that when a compensating network fails, the line connected thereto is rendered inoperative.
It is an object of the invention to provide a circuit arrangement with which signal transducers, in particular, compensating networks, can be connected to the feed and consumer lines directed over a program controlled exchange system, whereby the above mentioned disadvantages are avoided.